DE102013223250A1 - Printhead, printing device and method for applying a printing medium to a substrate, in particular a photovoltaic solar cell - Google Patents

Abstract

The invention relates to a printhead for applying a printing medium to a substrate, in particular a semiconductor structure such as a photovoltaic solar cell, with a printhead housing and a valve element, wherein the printhead housing has at least one feed opening for supplying pressure medium and a plurality of outlet openings for dispensing the pressure medium the valve element is rotatably supported in the printhead housing to control between a first pressurized operating condition in which the supply port is fluid-conductively connected to the exhaust ports and a second locked-state operation in which there is no fluid communication between the supply port and the exhaust ports. The invention is characterized in that the print head has at least one flushing medium connection and the valve element is designed and rotatably mounted in the print head housing such that in a third flushing operating state the flushing medium connection is fluid-conductively connected to the outlet openings and in the first and second operating state no fluid-conducting There is a connection between the flushing medium connection and the outlet openings.

Description

The invention relates to a print head, a printing device and a method for applying a printing medium to a substrate, in particular a semiconductor structure such as a photovoltaic solar cell, according to the preambles of claims 1, 9 and 11.

In industrial printing operations, particularly in the manufacture of semiconductor structures, it is often desirable to apply a print medium to the substrate. Such a printing medium may be a printing paste, which in particular contains a dopant for doping one or more regions of the semiconductor structure, which serves for forming a mask for subsequent process steps and / or which contains metal particles for forming a metallic contact structure.

The substrate may be a semiconductor structure in the manufacturing process, for example for producing a photovoltaic solar cell or an LED structure such as an OLED structure or an inorganic LED structure.

It is known to apply printing paste by means of screen printing on a semiconductor structure. Likewise is off US 5,151,377 discloses the use of a dispenser for applying a paste containing metal particles.

Out EP 2 196 316 a printing device is known with a printhead, which printhead has a plurality of outlet openings, which can be closed by means of a valve element arranged in the printhead.

The present invention has for its object to improve the prior art printhead, the printing device comprising the printhead and the method for applying the printing paste to the effect that increased precision and reliability is achieved.

This object is achieved by a printhead according to claim 1, a printing apparatus comprising such a printhead according to claim 9 and a method according to claim 12. Preferably embodiments of the printhead can be found in claims 2 to 8, the printing apparatus in claims 10 to 11 and Method in claims 13 to 16. Herewith the wording of all claims is explicitly included by reference in the description.

The inventive method is preferably designed for implementation by means of the print head according to the invention and / or the printing device according to the invention, in particular a preferred embodiment of the print head and / or the printing device. The printhead according to the invention and the printing device according to the invention are preferably designed to be carried out by means of the method according to the invention, in particular a preferred embodiment thereof.

The printhead according to the invention is designed for applying a printing medium to a substrate, in particular for application to a semiconductor structure such as, for example, a photovoltaic solar cell during its production.

The printhead has a printhead housing and a valve element. The printhead housing includes at least one supply port for supplying the print medium and a plurality of discharge ports for discharging the print medium.

The valve member is rotatably supported in the printhead housing to control between a first pressurized operating condition in which the supply port is fluid-conductively connected to the exhaust ports and a second inhibit operating condition in which there is no fluid communication between the supply port and the exhaust ports.

It is essential that the print head has at least one flushing medium connection and the valve element is designed and rotatably mounted in the print head housing, is fluid-conductively connected to the outlet openings and in the first and second operating state no connection, in particular no fluitleitende connection between flushing medium connection and the outlet openings.

The invention is based on the knowledge that, for the precise dispensing of the pressure medium at the plurality of outlet openings, in particular when using highly viscous pressure media having flow limits, the flow path between valve and outlet opening is advantageously made short. Furthermore, experiments have shown that a precise control of the pressure medium flow at several parallel outlet openings through a central valve arranged in a common feed channel is not possible with sufficient precision. If, however, a separate separate valve is arranged for each outlet opening, the influence of elasticities in the system is reduced and, moreover, the formation of pressure gradients between the outlet opening during startup and shutdown processes is prevented. Therefore, the print head according to the invention has a rotatably mounted in the print head housing valve element, wherein by rotating the valve element, the pressure medium output at the outlet openings can be allowed or prevented.

A further advantage of the device according to the invention is a self-reinforcing effect wherein the overpressure of the pressure medium in conjunction with the characteristic shaping of the closure shaft causes a force directed in the direction of the outlet openings, whereby the tightness of the valve increases with increasing pressure.

However, the investigations further revealed that high throughput and high precision are impeded by contaminants in the flow paths, in particular between the valve element and the outlet ports. In order to enable a high throughput and to prevent a reduction in the precision of the pressure medium output, it is therefore necessary to clean the print head, in particular the flow paths between the valve element and the outlet openings.

The printhead according to the invention allows rapid cleaning by flushing medium can be guided to the plurality of outlet openings in a simple manner by turning the valve element in the purge operating state via the flushing medium connection, so that flushing takes place, in particular the flow paths immediately in front of the outlet openings. The changeover between the individual operating states takes place in a simple manner by turning the valve element, so that in quick succession a cleaning of the print head e.g. between two Druckmediumaufbringvorgängen can take place.

As a result, in particular an industrial application with a high throughput rate and a low risk of failure is achieved.

Preferably, a flushing medium line is formed in the printhead, with a flushing medium connection and at least one flushing medium outlet, so that in the flushing operating state the flushing medium outlet of the valve element is arranged in the region of at least one outlet opening and fluid-conductively connected thereto. As a result, the supply of flushing medium to the outlet opening is ensured in a simple manner.

In particular, it is advantageous that, in the scavenging operating state, the scavenging medium outlet of the valve element is arranged in the region of the plurality of outlet openings and connected in a fluid-conducting manner to the latter. In this preferred embodiment, the flushing medium outlet thus covers a larger area, so that in the flushing operating state, the plurality of outlet openings are fluid-conductively connected to the flushing medium outlet of the flushing medium line.

In a further preferred embodiment, the flushing medium line has a flushing medium outlet for each of the plurality of outlet openings, so that in the flushing operating state each flushing medium outlet is arranged in the region of an outlet opening and fluid-conductively connected thereto. As a result, a defined supply of flushing medium is achieved at each outlet opening.

Preferably, the purge line is at least partially formed in the valve element. This ensures a secure separation of the flow paths between the pressure medium on the one hand and flushing medium on the other hand. A particularly advantageous embodiment results in this case by the flushing line is at least partially formed as an axial line, in particular as an axial bore in the valve element. In this preferred embodiment, the rinsing agent can be supplied in a simple manner in the valve element via the axial bore. Furthermore, starting from the axial bore, an approximately radially arranged recesses, in particular radial bores, are preferably provided, which connect the axial bore in the flushing operating state in each case to an outlet opening in a fluid-conducting manner. This results in the advantage that the flushing medium line can be formed in a simple manner by an axial and for each outlet opening in each case a radial bore in the valve element.

In a further preferred embodiment, the flushing medium line is formed between a valve wall facing the inner wall of the print head housing and the valve element, preferably by a trench-like recess of the valve element. Preferably, the flushing medium line is at least partially formed as a partial hollow cylinder between the printhead housing and the valve element, in particular by a partially hollow cylindrical recess of the valve element. This results in the advantage that no axial bore in the valve element must be made, which can simplify the manufacturing process, especially for long valve elements.

In this case, the flushing medium connection is preferably formed in the print head housing and arranged such that in the flushing operating state, the flushing medium connection is fluid-conductively connected to the flushing agent line.

Preferably, all of the plurality of outlet openings, in particular all outlet openings, are turned off simultaneously, i. a switching between the operating states B and C for all outlet openings takes place simultaneously.

In some applications, it is desirable that one or more of the outlet openings be selectively shut off separately from the remaining outlet openings.

In this preferred embodiment, some outlet openings are thus preferably switched off in time with respect to others; in particular, switching between the operating states B and C takes place for a subset of the outlet openings (FIG. 4 ) offset in time to the remaining outlet openings.

For example, when using the printhead for applying a printing paste to a semiconductor structure, it is desirable for non-rectangular semiconductor structures such as semiconductor structures on so-called pseudo-square wafers to separately connect and disconnect marginal outlet openings so that a pressure medium output of only the marginal outlet openings is avoided these are not yet above the semiconductor substrate.

The valve element is therefore preferably designed such that in a fourth partial pressure operating state, the feed opening is fluid-conductively connected only to a subset of the plurality of outlet openings, in particular that marginal outlet openings are not included in the subset. In this advantageous embodiment, thus also by rotation of the valve element in a simple manner, an output of the pressure medium can be achieved only on the subset of the plurality of outlet openings.

It is within the scope of the invention to provide additional partial pressure operating states in further advantageous embodiments in which different subsets of the plurality of outlet openings are fluid-conductively connected to the feed opening, whereas the outlet openings not belonging to the respective subset are not fluid-conductively connected to the feed opening. As a result, adaptation to the desired shape of the substrate, in particular of the semiconductor structure, can be achieved by a plurality of partial-pressure operating states; in particular, it is also possible, for example, to apply print medium lines to round or polygonal substrates.

In a further advantageous embodiment, a common fluid line is formed between the feed opening and a plurality of outlet openings. This results in the advantage that there is a higher pressure medium throughput and thus a lower risk of contamination or blockages in the common fluid line. When the valve element is designed with partial-pressure operating states as described above, it is particularly advantageous to connect such outlet openings, which are fluid-conductively connected to the feed opening in all pressure operating states, to the feed opening via a common fluid line.

Preferably, therefore, the common fluid line between the feed opening and the subset of the plurality of outlet openings is formed, in particular for the not contained in the subset outlet preferably a further fluid line, in particular preferably each formed a further fluid line.

In order to avoid a negative influence on the pressure medium, in particular of highly viscous printing pastes, a fluid line with a constant cross-section and preferably the same channel geometry between the feed opening and the outlet opening is preferably formed for each outlet opening.

Therefore, a pressure medium channel is preferably formed for each outlet opening, which is fluid-conductively connected to the feed opening in the pressure operating state, and each pressure medium channel preferably has a constant cross-section at least between the valve element and outlet opening. In particular, in a preferred embodiment, in which each pressure medium channel is at least partially formed as a recess of the valve element, preferably for each pressure medium channel formed through the valve member portion of the pressure medium channel and the portion of the pressure medium channel between the valve element and outlet opening has a constant cross-section.

The object underlying the invention is further achieved by a printing device according to claim 10.

The printing device according to the invention for applying a printing medium to a substrate, in particular to a semiconductor structure, such as a photovoltaic solar cell, has a pressure medium reservoir and a Druckmediumpumpmittel and a printhead according to the invention, in particular a preferred embodiment thereof on. The pressure medium pumping means is fluid-conductively connected to the pressure medium reservoir and the supply port of the print head to supply print medium to the print head.

Preferably, the pressure device comprises an actuating means for the valve element. This actuating means is preferably designed for rotating the valve element relative to the printhead housing. In order to allow a precise change of the operating conditions, the actuating means is preferably designed to rotate the valve element at a peripheral speed in the range of 10 mm / s to 10 m / s and / or by switching times between the operating states in the range 150 μs-150 ms to enable.

It is within the scope of the invention to provide conventional control means, in particular a control unit such as a microprocessor and / or a computer to control the printing process and in this case in particular by means of control signals to rotate the valve element by means of the actuating means to the respective to set the desired operating state.

The object underlying the invention is further achieved by a method for applying a printing medium to a substrate according to claim 13.

The inventive method for applying a printing medium to a substrate, in particular to a semiconductor structure such as a photovoltaic solar cell by means of a printhead according to the invention, in particular an advantageous embodiment thereof.

The method comprises the following method steps:
In a method step A, the printhead is set up in the printing operating state.

In a method step B, the printing medium is fed to the print head and the print medium is discharged from the outlet openings onto the substrate.

In a method step C, the printhead is set in the blocking operating state and the supply of printing medium to the printhead is ended.

It is essential that, in a method step D, the printhead is set into the rinsing operating state and a supply or removal of rinsing medium to the rinsing medium connection so that the rinsing medium flows through the printhead and exits at the outlet openings, and thus a rinsing process takes place.

The flushing medium is preferably supplied via the flushing medium connection, so that the flushing medium connection acts as flushing medium inlet for the print head and the flushing medium is discharged at the outlet openings. Likewise, it is within the scope of the invention to remove the flushing medium via the flushing medium connection, in particular to suck it off, so that the flushing medium is supplied via the outlet openings and discharged via the flushing medium connection (as flushing sleeve outlet).

Preferably, compressed air is used as flushing medium. The compressed air can be supplied via the flushing medium connection, so that it is likewise within the scope of the invention to use as the flushing medium a solvent, in particular acetone, isopropyl alcohol and / or terpineol.

In particular, when using compressed air as the flushing medium, it is advantageous to suck the compressed air through the flushing medium connection. Because this allows the ambient air to be used for rinsing in a simple manner and the impurities are not output from the outlet openings, but discharged via the flushing medium connection.

The printhead according to the invention, the printing device according to the invention and the method according to the invention can be used for coating any desired substrates, for example silicon wafers, in particular in the production of various types of semiconductor structures. In particular, use in the production of large-area semiconductor structures, such as LED, OLED or photovoltaic solar cells is advantageous, since line-like structures are often to be produced by applying printing medium, in particular a printing paste.

In particular, use for producing metallic contacting structures, preferably by using a printing paste containing metal particles, is advantageous. Such metallic contact structures are used in particular in photovoltaic solar cells. Typically, a metal contacting grid for discharging the charge carriers is arranged on the side facing the incident radiation when the solar cell is used. The grid typically has a plurality of line-like, parallel contacting fingers. In particular for the production of these contacting fingers, the print head according to the invention, the printing device according to the invention and the method according to the invention are particularly suitable.

The print head is preferably designed such that no further line for the print medium is arranged between the outlet openings and the semiconductor substrate, i. H. that the pressure medium is applied directly to the semiconductor substrate after exiting the outlet openings.

Preferably, the print head is formed such that the flow path between the valve element and the outlet opening at each of the plurality of outlet openings is in each case less than 5 cm, preferably less than 1 cm, particularly preferably less than 0.3 cm.

The printing process can be carried out in a manner known per se, in particular as in EP 2 196 316 B1 be executed described. Thus, typically, the printhead will become relative to the semiconductor substrate and, in particular, perpendicular to one The longitudinal extent of the printhead is moved during the printing operation to achieve application of multiple parallel line-like print media strands on the semiconductor substrate.

The execution openings are preferably arranged along a straight line. Further preferred features and embodiments are explained below with reference to the figures and embodiments. Showing:

1a to 1c a first embodiment of a print head according to the invention;

2a to 2c A second embodiment of a printhead according to the invention and

3 a perspective view of an application example of a third embodiment of a printhead according to the invention.

In the figures, like reference numerals designate like or equivalent elements.

In the 1a to 1c a first embodiment of a printhead according to the invention is shown schematically.

1a and 1b such as 2a and 2 B show radial sectional views; 1c such as 2c each show an axial sectional view.

The printhead according to the first embodiment has a printhead housing 1 on, which has a cylindrical recess. In the cylindrical recess is a valve element 2 rotatably mounted. The rotation can be in the 1a and 1b clockwise or counterclockwise around an in 1a shown pivot point D done. Accordingly, in 1c the axis of rotation D of the valve element 2 shown.

The printhead housing 1 has a feed opening 3 for supplying print medium. Furthermore, the printhead housing 1 a variety of outlet openings 4 to eject the print media. Exemplary are in 1c the marginal outlet openings 4a and 4b and two middle outlet openings 4 characterized.

As already described, the valve element 2 rotatable in the printhead housing 1 stored. 1a in this case shows the rotational position of a printing-operating state: In this rotational position, a printing medium such as a printing paste on the supply port 3 be fed (flow path indicated by arrows), the pressure medium passes through a conduit path, which between the valve element 2 and an inner wall of the printhead body 1 is formed and finally occurs at the outlet openings 4 out.

As in 1 seen, covers the feed opening 3 in the axial direction, the entire pressure-active width of the print head. The valve element 2 points, however, for each outlet opening 4 in each case a part-ring-like recess (in the form of a hollow part cylinder with a rectangular cross-section), see the reference numerals by way of example 2a and 2 B for the marginal part-ring-like recesses of the valve element 2 in 1c ). The printing medium is thus by means of a feed opening 3 supplied and through the partial ring-like recesses 2a . 2 B each an outlet opening 4 fed.

In a second blocking mode, the valve element becomes 2 opposite the printhead housing 1 turned, so that in 1a S marked area of the valve element 2 the outlet openings 4 covered and thus the pressure medium output is interrupted.

In 1b Finally, a third rinse operating state is shown:
The valve element 2 has a flushing medium connection 5 on, which in the embodiment according to 1 as axial bore of the valve element 2 is trained. Furthermore, the valve element 2 to each outlet opening 4 each designed as a radial bore radial flushing medium line 6 on.

As in 1b can be seen, in the purge mode, the valve element 2 rotated so that the radial flushing medium line 6 each with the associated outlet opening 4 fluidly connected. In this operating state, therefore, rinsing agent via the flushing medium connection 5 are supplied, which passes through the axial Spülmittelleitung and the respective radial Spülmittelleitungen 4 to the outlet openings 4 so that rinsing of the printhead takes place.

The printhead according to 1 thus allows an output of pressure medium as well as a precise shutdown and a purge only depending on the rotational position of the valve element 2 relative to the printhead housing 1 ,

For the use of highly viscous pastes as a pressure medium, it is advantageous that the distance A between the valve element 2 and the outlet openings 4 is low. At the in 1 illustrated embodiment, the distance A is 0.5 mm.

The dashed line 7 according to 1a describes a preferred modification of the first embodiment with edge shutdown:
In this embodiment, the partial ring-like recesses 2a . 2 B of the valve element 2 executed differently to the remaining part-ring-like recesses: The marginal part-ring-like recesses overlap a smaller angular range compared to the other part-ring-like recesses. As in 1A can be seen, the partial ring-like recess not shown in phantom overlaps an angular range over 200 °, whereas the part-ring-like recess 2 B , which are at the dotted line 7 ends, covers an angle range less than 200 °.

At the in 1a illustrated rotational position of the valve element 2 Thus, a partial pressure operating state is shown: the marginal outlet openings 4a and 4b are closed by the valve element (there is no fluid-conducting connection between the feed opening 3 and the outlet openings 4a and 4b because like in 1a as can be seen, the flow path of the printing paste at the dashed line 7 ends.

In this partial pressure operating state, there is thus no pressure medium output at the outlet openings 4a and 4b , but only at the remaining outlet openings 4 , As a result, for example, the formation of metallic contacting fingers is also possible with pseudo-square wafers having correspondingly shorter fingers in the edge regions of the wafer.

Will the valve element 2 however, continue clockwise according to 1a turned, so that with the dashed line 7 marked area at the left edge of the outlet opening 4 is arranged so can pressure medium from all outlet openings 4 be issued.

In 2 a second embodiment of a printhead according to the invention is shown. To avoid repetition, only the essential differences from the first exemplary embodiment will be discussed below:
In the second embodiment of a printhead according to the invention, the flushing medium line is partially between the valve element 2 and inner wall of the printhead housing 1 educated. Accordingly, the flushing medium connection 5 formed in the printhead housing, so that in the purge operating position according to 2 B a fluid-conducting connection between Spülmediumanschluss 5 and outlet opening 4 consists. The flow path between feed opening 3 and outlet opening 4 is locked accordingly in this operating state.

Conversely, in the in 2a illustrated pressure operating state of the flow path between flushing medium connection 5 and outlet opening 4 as well as the flow path between feed opening 3 and flushing medium connection 5 locked, whereas a fluid-conducting connection between the feed opening 3 and outlet opening 4 consists.

In 3 Finally, an application example is shown schematically and in perspective to explain an embodiment of a printing device according to the invention and a method according to the invention:

To produce a photovoltaic solar cell, printing paste containing metal particles on a pseudo-square wafer W is applied in a plurality of parallel lines in order to form metallic contacting fingers.

For this purpose, the wafer W in the direction indicated by an arrow Dispenserichtung under the print head housing 1 moved through. The printhead can work according to 1 or 2 be educated.

The printhead is part of a printing device according to the invention, which further comprises a pressure medium reservoir 7 having integrated Druckmediumpumpmittel, so that via a line pressure medium of the feed opening 3 of the printhead body 1 can be fed.

This is done by turning the valve element 2 by means of an actuating device designed as an electric motor 8th initially set a partial pressure operating state, so that no pressure medium is output at the marginal outlet openings. In the area of the chamfered corners (two of the four beveled corners are marked by dashed circles) of the pseudo square wafer, no print medium is thus initially applied.

Once the wafer W is placed in full width under the printhead, turning the valve member will cause it to rotate 2 the pressure operating state is set in which over all the outlet openings 4 Print media is output. Once the opposing beveled corners of the pseudo square wafer reach the area under the print head, turn by turning the valve element 2 set the partial pressure operating state, so that only on the non-edge outlet openings pressure medium is output. Finally, if the entire wafer is printed, turn by turning the valve element 2 the blocking operating state is set so that no pressure medium emerges from the outlet openings more.

The actuating means may also be designed as a magnetic switch or pneumatic cylinder. Preferably, the actuating means is formed to allow switching times between the operating states in the range 150 μs to 150 ms.

After passing through the wafer, a flushing medium collecting tray is moved under the printing head and by turning the valve element 2 the purge mode is established. By means of a compressed air source 9 compressed air becomes a flushing medium connection 5 led the printhead, which via the flushing medium line to all outlet openings 4 is passed, so that a cleaning of the printhead and in particular all the outlet openings 4 he follows.

Subsequently, by turning the valve element 2 the partial printing operating state is set again and the next wafer can be printed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5151377 [0004]
• EP 2196316 [0005]
• EP 2196316 B1 [0051]

Claims (16)

Printhead for applying a printing medium to a substrate, in particular a semiconductor structure such as a photovoltaic solar cell, having a printhead housing ( 1 ) and a valve element ( 2 ), wherein the printhead housing at least one feed opening ( 3 ) for supplying pressure medium and a plurality of outlet openings ( 4 ) for dispensing the pressure medium, wherein the valve element rotatably in the printhead housing ( 1 ) between a first pressure operating state, in which the feed opening in fluid communication with the outlet openings ( 4 ) and a second blocking operating state, in which no fluid-conducting connection between feed opening ( 3 ) and the outlet openings, to be controlled, characterized in that the print head at least one flushing medium connection ( 5 ) and the valve element ( 2 ) are formed and rotatable in the printhead housing ( 1 ) is mounted, that in a third rinsing operating state of the flushing medium connection fluid-conducting with the outlet openings ( 4 ) is connected and in the first and second operating state, no fluid-conducting connection between flushing medium connection ( 5 ) and the outlet openings ( 4 ) consists. Printhead according to Claim 1, characterized in that a flushing medium line is formed in the print head, with a flushing medium connection ( 5 ) and at least one flushing medium outlet, so that in the flushing operating state the flushing medium outlet of the valve element is in the region of at least one outlet opening ( 4 ) is arranged and fluid-conductively connected thereto, preferably that in the scavenging operating state of the flushing medium outlet of the valve element in the region of the plurality of outlet openings ( 4 ) and is connected in a fluid-conducting manner with these and / or that the flushing medium line has a flushing medium outlet for each outlet opening and that in the flushing operating state each flushing medium outlet is arranged in the region of an outlet opening and is connected in a fluid-conducting manner with it. Printhead according to claim 2, characterized in that the flushing medium line at least partially in the valve element ( 2 ) is formed, in particular as an axial line, preferably axial bore in the valve element ( 2 ) is trained. Printhead according to claim 2, characterized in that the flushing medium line between a valve element ( 2 ) facing the inner wall of the print head housing and the valve element ( 2 ) is formed, in particular by a trench-like recess of the valve element. Printhead according to claim 4, characterized in that the flushing medium connection ( 5 ) in the printhead housing ( 1 ) is formed and arranged such that in the purge operating state of the flushing medium connection ( 5 ) is fluidly connected to the detergent line. Printhead according to one of the preceding claims, characterized in that in a fourth partial-pressure operating state the feed opening ( 3 ) with only a subset of the plurality of outlet openings ( 4 ) is fluid-conductively connected, in particular, that peripheral outlet openings ( 4 ) are not included in the subset. Printhead according to one of the preceding claims, characterized in that a common fluid line between feed opening ( 3 ) and a plurality of outlet openings ( 4 ) is trained. Printhead according to claim 6 and claim 7, characterized in that the common fluid line between feed opening ( 3 ) and the subset of the plurality of outlet openings ( 4 ), in particular that for the outlet openings not contained in the subset ( 4 ) at least one further fluid conduit is formed, preferably, that for each not included in the subset outlet opening in each case a further fluid conduit is formed. Printing device for applying a printing medium to a substrate, in particular a semiconductor structure such as a photovoltaic solar cell, having a pressure medium reservoir ( 7 ) and a pressure medium pumping means and a printhead according to one of the preceding claims, wherein the pressure medium pumping means is in fluid conduction with the pressure medium reservoir ( 7 ) and the feed opening ( 3 ) of the printhead for feeding print medium to the printhead. Printing device according to claim 9, characterized in that the printing device comprises an actuating means for the valve element ( 2 ), in particular that the actuating means for rotating the valve element relative to the printhead housing ( 1 ) is trained. Printing device according to claim 10, characterized in that the printing device comprises a control unit, which is designed to cooperate with the actuating means, that by means of the control unit for each operating state, a rotational position of the valve element relative to the printhead housing ( 1 ) can be specified. Method for applying a printing medium to a substrate, in particular a Semiconductor structure such as a photovoltaic solar cell, by means of a printhead according to one of claims 1 to 9, comprising the following method steps: A setting up the printhead in the printing operating state; B feeding the print media to the printhead and ejecting the print media from the exhaust ports ( 4 ) on the substrate; C, setting up the printhead in the lock-up mode and terminating the supply of print medium to the printhead; characterized in that in a method step D, an adjustment of the print head in the rinsing operating state and supplying rinsing medium to the rinsing medium connection ( 5 ) he follows. A method according to claim 12, characterized in that a switching between the operating states B and C for all outlet openings ( 4 ) takes place simultaneously. A method according to claim 12, characterized in that a switching between the operating states B and C for a subset of the outlet openings ( 4 ) takes place offset in time to the remaining outlet openings. Method according to one of claims 12 to 14, characterized in that as flushing medium one or more of the group - gases, in particular air, - solvent, in particular acetone and / or terpineol - thinner, in particular a substance already contained in the printing medium is used. Method according to one of claims 12 to 15, characterized in that in process step D at the flushing medium connection ( 5 ) a suction of the flushing medium takes place.

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